Obesity has reached pandemic proportion in the United States with 55% of adults and 25% of children classified as overweight. Increased meal portion sizes, a sedentary lifestyle, the proliferation of fad diets, and the increased carbohydrate calorie intake associated with low fat diets all contribute to this national health crisis. Some attributes of obesity include: 365,000 deaths per year related to morbid obesity, which is the second leading cause of death in U.S. behind tobacco (435,000 per year); high incidence of depression; higher incidence and poorer prognosis for cancers such as esophageal, prostate, colon, ovarian, cervical, breast, uterine cancer more common; as well as untold physical, economic and psychological impacts.
As obesity progresses, the affected individuals develop medical comorbidities at alarming proportions. These include diabetes mellitus, heart disease, hypertension, dyslipidemia, degenerative joint disease, and numerous others. The five-year death rate among the untreated morbidly obese is over 6%, and this risk is reduced by 89% after successful weight loss surgery has been performed. Diabetes, which affects almost 80% of morbidly obese individuals, is improved in 85% after substantial weight loss and cured in 75%. Coronary artery disease is improved in 45%, hypertension in 55%, and the morbidity and mortality of joint replacement surgery markedly reduced in patients able to achieve meaningful weight loss, typically after weight loss or bariatric surgery.
In extreme cases of morbid obesity that are untreatable through behavioral modification, diet and increased exercise, bariatric surgery is a dangerous final approach to reduce a patient's weight. Weight loss operations vary in aggressiveness, yet share the common feature of reducing or removing the stomach volume with an associated rearrangement of the small intestine to limit the amount of calories both ingested and absorbed. Some procedures solely restrict intake, and are known as restrictive procedures, while others combine restrictive and malabsorptive components to achieve even greater and more sustained weight loss. Unfortunately, the resultant weight loss is invariably accompanied by poor vitamin absorption, a predisposition to malnutrition, and potentially severe or life-threatening metabolic complications. Severe and life-threatening complications may result from surgery because of intestinal leaks from one or more of the intestinal anastomoses, pulmonary complications related to comorbid conditions like sleep apnea, deep venous thrombosis with pulmonary embolism, or postoperative myocardial infarction. Additionally, owing to the radical nature of bariatric surgery, reversal of the procedure upon reaching an optimal weight or suffering intolerable side effects is virtually impossible for many patients.
Another approach to addressing obesity has been the deployment of a gastric and/or intestinal barrier that limits nutrient absorption by creating a physical barrier between the chymal mixture and intestinal epithelial cells. While such barriers have proven effective in reducing subject weight and are reversible through the retrieval of such a barrier, such barriers have met with limited acceptance. Representative barriers are disclosed in U.S. Pat. Nos. 4,134,505; 4,403,604; 4,416,267; and 5,306,300. Safety concerns have developed around these devices associated with barrier dislodgement or kinking, resulting in obstruction or barrier erosion through portions of the gastrointestinal tract resulting in infection, sepsis, and the need for emergency surgery. Additionally, the necessity for a second surgical procedure to safely collapse and retrieve a barrier in response to an intended or emergency retrieval also remains a concern.
Thus, there exists a need for a digestive tract barrier that disintegrates in a controlled manner after deployment. There also exists a need for a variant barrier deployable to treat symptoms of colitis and Crohn's disease.